Multi-link aggregation method and device

ABSTRACT

Embodiments of the present invention disclose a multi-link aggregation method, including: establishing, by a first device, a transparent transmission channel with a second device, where the transparent transmission channel spans multiple links connected to the first device and the second device; performing, by the first device, network address translation on a first target packet to obtain a second target packet; and transmitting, by the first device, the second target packet to the second device through the transparent transmission channel, so that the second device performs network address translation on the second target packet to obtain a third target packet, and the second device sends the third target packet to a target device identified by destination address information of the first target packet.

This application is a continuation of International Application No.PCT/CN2014/072192, filed on Feb. 18, 2014, which claims priority toChinese Patent Application No. 201310063115.0, filed on Feb. 28, 2013,both of which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of communications, and inparticular, to a multi-link aggregation method and a device.

BACKGROUND

Continuous development of access technologies gives rise to a situationof reality in which multiple access technologies coexist, for example, adigital subscriber line (DSL) access technology, a fiber access(Fiber-To-The-X, FTTX) technology, a Long Term Evolution (LTE) accesstechnology, and an E1 access technology, and many network devices maysupport two or more access technologies simultaneously.

Currently, in the industry, multi-link aggregation is implemented mainlyby establishing a virtual private network (VPN) tunnel between auser-side access device and a network-side server, that is,cross-network forwarding and aggregation of packets are implemented byusing multiple access technologies simultaneously supported by a networkdevice.

However, in an implementation process of the foregoing technologies, apacket is directly transmitted on the VPN tunnel, and the number ofpacket encapsulation layers and a packet length are increased.Consequently, the packet transmission efficiency in the foregoingtechnical solution is low, and a VPN solution further requiresadditional network address resources.

SUMMARY

Embodiments of the present invention provide a multi-link aggregationmethod and a device, which can implement multi-link aggregation and mayimprove the packet transmission efficiency and save network addressresources.

According to a first aspect, an embodiment of the present inventionprovides a multi-link aggregation method, including establishing, by afirst device, a transparent transmission channel with a second device,where the transparent transmission channel spans multiple linksconnected to the first device and the second device; performing, by thefirst device, network address translation on a first target packet toobtain a second target packet; and transmitting, by the first device,the second target packet to the second device through the transparenttransmission channel, so that the second device performs network addresstranslation on the second target packet to obtain a third target packet,and the second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

In a first possible implementation manner, after the performing, by thefirst device, network address translation on a first target packet toobtain a second target packet, and before the transmitting, by the firstdevice, the second target packet to the second device through thetransparent transmission channel, the method further includes executing,by the first device, a link bonding policy, and selecting a target linkfrom the links that are connected to the first device and the seconddevice and spanned by the transparent transmission channel; andencapsulating, by the first device, the second target packet with thetarget link to obtain a fourth target packet. The transmitting, by thefirst device, the second target packet to the second device through thetransparent transmission channel, includes transmitting, by the firstdevice, the fourth target packet to the second device through the targetlink.

With reference to the first possible implementation manner of the firstaspect, in a second possible implementation manner, the executing, bythe first device, a link bonding policy, and selecting a target linkfrom the links that are connected to the first device and the seconddevice and spanned by the transparent transmission channel, includeanalyzing, by the first device, a bandwidth parameter of each link thatis connected to the first device and the second device and spanned bythe transparent transmission channel; and analyzing, by the first deviceaccording to the bandwidth parameter of each link, a speed and a packetlength for sending to a buffer of the link, and selecting the targetlink from the multiple links connected to the first device and thesecond device. The transmitting, by the first device, the fourth targetpacket to the second device through the target link, includes sending,by the first device, the fourth target packet to the buffer of thetarget link according to the speed and packet length for sending to thebuffer of the target link, and sending the fourth target packet in thebuffer to the second device through the target link.

According to a second aspect, an embodiment of the present inventionprovides another multi-link aggregation method, including receiving, bya first device through a transparent transmission channel established inadvance, a second response packet sent by a second device. Thetransparent transmission channel spans multiple links connected to thefirst device and the second device, and the second response packet is aresponse packet obtained by the second device by performing networkaddress translation on a first response packet, where the first responsepacket is a response packet that is received by the second device from atarget device and sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device.The method further includes performing, by the first device, networkaddress translation on the second response packet to obtain a thirdresponse packet; and sending, by the first device, the third responsepacket to a device identified by source address information of thetarget packet.

According to a third aspect, an embodiment of the present inventionprovides a multi-link aggregation method, including establishing, by asecond device, a transparent transmission channel with a first device,where the transparent transmission channel spans multiple linksconnected to the second device and the first device; receiving, by thesecond device through the transparent transmission channel, a secondtarget packet sent by the first device, where the second target packetis a packet obtained by the first device by performing network addresstranslation on a first target packet; performing, by the second device,network address translation on the second target packet to obtain athird target packet; and sending, by the second device, the third targetpacket to a target device identified by destination address informationof the first target packet.

According to a fourth aspect, an embodiment of the present inventionprovides a multi-link aggregation method, including performing, by asecond device, network address translation on a first response packet toobtain a second response packet, where the first response packet is aresponse packet that is received by the second device from a targetdevice and sent by the target device in response to a target packet thatis sent in advance by a first device to the target device; andtransmitting, by the second device, the second response packet to thefirst device through a transparent transmission channel established inadvance, so that the first device performs network address translationon the second response packet to obtain a third response packet, and thefirst device sends the third response packet to a device identified bysource address information of the target packet, where the transparenttransmission channel spans multiple links connected to the first deviceand the second device.

In a first possible implementation manner, after the performing, by thesecond device, network address translation on the first response packetto obtain the second response packet, and before the sending, by thesecond device, the second response packet to the first device throughthe transparent transmission channel, the method further includesexecuting, by the second device, a link bonding policy, and selecting atarget link from the links that are connected to the second device andthe first device and spanned by the transparent transmission channelestablished in advance; and encapsulating, by the second device, thesecond response packet with the target link to obtain a fourth responsepacket. The sending, by the second device, the second response packet tothe first device through the transparent transmission channel, includessending, by the second device through the target link, the fourthresponse packet to an interface, on which the target link isestablished, of the first device.

With reference to the first possible implementation manner of the fourthaspect, in a second possible implementation manner, the executing, bythe second device, a link bonding policy, and selecting a target linkfrom the links that are connected to the second device and the firstdevice and spanned by the transparent transmission channel establishedin advance, include receiving, by the second device, a bandwidthparameter, which is sent by the first device, of each link that isconnected to the second device and the first device and spanned by thetransparent transmission channel established in advance, where thebandwidth parameter of each link is a bandwidth parameter of each linkobtained by the first device by analysis; and analyzing, by the seconddevice according to the bandwidth parameter of each link, a speed and apacket length for sending to a buffer of the link, and selecting thetarget link from the multiple links that are connected to the seconddevice and the first device and spanned by the transparent transmissionchannel established in advance. The sending, by the second devicethrough the target link, the fourth response packet to an interface, onwhich the target link is established, of the first device, includessending, by the second device, the fourth response packet to the bufferof the target link according to the speed and packet length for sendingto the buffer of the target link, and sending the fourth response packetin the buffer to the interface, on which the target link is established,of the second device.

According to a fifth aspect, an embodiment of the present inventionprovides a network device, including an establishing unit, a translatingunit, and a sending unit, where the establishing unit is configured toestablish a transparent transmission channel with a second device, wherethe transparent transmission channel spans multiple links connected tothe network device and the second device. The translating unit isconfigured to perform network address translation on a first targetpacket to obtain a second target packet. The sending unit is configuredto transmit the second target packet to the second device through thetransparent transmission channel, so that the second device performsnetwork address translation on the second target packet to obtain athird target packet, and the second device sends the third target packetto a target device identified by destination address information of thefirst target packet.

In a first possible implementation manner, the device further includes aselecting unit configured to execute a link bonding policy, and select atarget link from the links that are connected to the network device andthe second device and spanned by the transparent transmission channel;and an encapsulating unit configured to encapsulate the second targetpacket with the target link to obtain a fourth target packet. Thesending unit is further configured to transmit the fourth target packetto the second device through the target link.

With reference to the first possible implementation manner of the fifthaspect, in a second possible implementation manner, the selecting unitincludes a first analyzing unit configured to analyze a bandwidthparameter of each link that is connected to the network device and thesecond device and spanned by the transparent transmission channel. Asecond analyzing unit is configured to analyze, according to thebandwidth parameter of each link, a speed and a packet length forsending to a buffer of the link, and select the target link from themultiple links connected to the network device and the second device.The sending unit is further configured to send the fourth target packetto the buffer of the target link according to the speed and packetlength for sending to the buffer of the target link, and send the fourthtarget packet in the buffer to the second device through the targetlink.

According to a sixth aspect, an embodiment of the present inventionprovides a network device, including a receiving unit, a translatingunit, and a sending unit, where the receiving unit is configured toreceive, through a transparent transmission channel established inadvance, a second response packet sent by a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device, and the second response packet is aresponse packet obtained by the second device by performing networkaddress translation on a first response packet, where the first responsepacket is a response packet that is received by the second device from atarget device and sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device.The translating unit is configured to perform network addresstranslation on the second response packet to obtain a third responsepacket. The sending unit is configured to send the third response packetto a device identified by source address information of the targetpacket.

According to a seventh aspect, an embodiment of the present inventionprovides a network device, including an establishing unit, a receivingunit, a translating unit, and a sending unit. The establishing unit isconfigured to establish a transparent transmission channel with a firstdevice, where the transparent transmission channel spans multiple linksconnected to the network device and the first device. The receiving unitis configured to receive, through the transparent transmission channel,a second target packet sent by the first device, where the second targetpacket is a packet obtained by the first device by performing networkaddress translation on a first target packet. The translating unit isconfigured to perform network address translation on the second targetpacket to obtain a third target packet. The sending unit is configuredto send the third target packet to a target device identified bydestination address information of the first target packet.

According to an eighth aspect, an embodiment of the present inventionprovides a network device, including a translating unit and a sendingunit. The translating unit is configured to perform network addresstranslation on a first response packet to obtain a second responsepacket, where the first response packet is a response packet that isreceived by the network device from a target device and sent by thetarget device in response to a target packet that is sent in advance bya first device to the target device. The sending unit is configured totransmit the second response packet to the first device through atransparent transmission channel established in advance, so that thefirst device performs network address translation on the second responsepacket to obtain a third response packet, and the first device sends thethird response packet to a device identified by source addressinformation of the target packet, where the transparent transmissionchannel spans multiple links connected to the first device and thesecond device.

In a first possible implementation manner, the device further includes aselecting unit, configured to execute a link bonding policy, and selecta target link from the links that are connected to the network deviceand the first device and spanned by the transparent transmission channelestablished in advance. An encapsulating unit is configured toencapsulate the second response packet with the target link to obtain afourth response packet. The sending unit is further configured to send,through the target link, the fourth response packet to an interface, onwhich the target link is established, of the first device.

With reference to the first possible implementation manner of the eighthaspect, in a second possible implementation manner, the selecting unitincludes a receiving subunit configured to receive a bandwidthparameter, which is sent by the first device, of each link that isconnected to the network device and the first device and spanned by thetransparent transmission channel established in advance, where thebandwidth parameter of each link is a bandwidth parameter of each linkobtained by the first device by analysis. An analyzing unit isconfigured to analyze, according to the bandwidth parameter of eachlink, a speed and a packet length for sending to a buffer of the link,and select the target link from the multiple links that are connected tothe second device and the first device and spanned by the transparenttransmission channel established in advance. The sending unit is furtherconfigured to send the fourth response packet to the buffer of thetarget link according to the speed and packet length for sending to thebuffer of the target link, and send the fourth response packet in thebuffer to the interface, on which the target link is established, of thesecond device.

In the foregoing technical solutions, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device performs networkaddress translation on a first target packet to obtain a second targetpacket; and the first device transmits the second target packet to thesecond device through the transparent transmission channel, so that thesecond device performs network address translation on the second targetpacket to obtain a third target packet, and the second device sends thethird target packet to a target device identified by destination addressinformation of the first target packet. In this way, network addresstranslation is performed when a packet is transmitted between the firstdevice and the second device, which saves network address resources,reduces the number of target packet encapsulation layers, and therebyimproves the packet transmission efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present invention, and a person ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 2 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 3 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 4 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 5 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 6 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 7 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 8 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 9 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention;

FIG. 10 is a schematic flowchart of another multi-link aggregationmethod according to an embodiment of the present invention;

FIG. 11 is a schematic flowchart of another multi-link aggregationmethod according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a network device accordingto an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 15 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 16 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 17 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 18 is a schematic structural diagram of a multi-link aggregationsystem according to an embodiment of the present invention;

FIG. 19 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 20 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 21 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 22 is a schematic structural diagram of a multi-link aggregationsystem according to an embodiment of the present invention;

FIG. 23 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 24 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 25 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 26 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 27 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention;

FIG. 28 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention; and

FIG. 29 is a schematic structural diagram of a multi-link aggregationsystem according to an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present invention with reference to the accompanyingdrawings in the embodiments of the present invention. Apparently, thedescribed embodiments are merely a part rather than all of theembodiments of the present invention. All other embodiments obtained bya person of ordinary skill in the art based on the embodiments of thepresent invention without creative efforts shall fall within theprotection scope of the present invention.

FIG. 1 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 1,the method includes the following.

101. A first device establishes a transparent transmission channel witha second device, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

102. The first device performs network address translation (NAT) on afirst target packet to obtain a second target packet.

103. The first device transmits the second target packet to the seconddevice through the transparent transmission channel, so that the seconddevice performs NAT on the second target packet to obtain a third targetpacket, and the second device sends the third target packet to a targetdevice identified by destination address information of the first targetpacket.

Optionally, when receiving the second target packet, the second devicemay perform NAT on the packet, and send a packet obtained throughtranslation to the target device.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the first device and the second device are two differentdevices. For example, when the first device is an access device, thesecond device may be a server; when the first device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a Global System of Mobilecommunication (GSM) link, a cable link, a fiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a genericrouting encapsulation (GRE) tunnel, a point-to-point transmissionchannel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device performs NAT on afirst target packet to obtain a second target packet; and the firstdevice transmits the second target packet to the second device throughthe transparent transmission channel, so that the second device performsNAT on the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the first device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 2 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 2,the method includes the following.

201. A first device establishes a transparent transmission channel witha second device, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

Optionally, the spanning may indicate that the transparent transmissionchannel is borne on the multiple links connected to the first device andthe second device, and that a packet of a source point of thetransparent transmission channel may be transmitted to an end point ofthe transparent transmission channel through any link that thetransparent transmission channel spans.

202. The first device performs NAT on a first target packet to obtain asecond target packet.

Optionally, the first target packet may be an uplink packet. Optionally,the first target packet may be one or more packets sent by a user-sidedevice (for example, a home terminal or a mobile terminal), and thefirst device is an access device or a gateway device.

Optionally, the first target packet may be a downlink packet.Optionally, the first target packet may be one or more packets sent byan Internet device, and the first device is an aggregation server.

Optionally, the NAT may translate source address information and sourceport information of the first target packet into address information andport information of the first device.

203. The first device executes a link bonding policy (for example, aLink Channel Policy), and selects a target link from the links that areconnected to the first device and the second device and spanned by thetransparent transmission channel.

204. The first device encapsulates the second target packet with theselected target link to obtain a fourth target packet.

205. The first device transmits the fourth target packet to the seconddevice through the target link, so that the second device decapsulatesthe fourth target packet to obtain a third target packet, and that thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

Optionally, that the first device performs NAT on a first target packetmay be that the first device translates the source address informationand source port information of the first target packet into the addressinformation and port information of the first device.

Optionally, that the second device restores and obtains a third targetpacket may be that the fourth target packet is decapsulated to obtainthe second target packet; and that the second device translates sourceaddress information and source port information of the second targetpacket into address information and port information of the seconddevice, the second device translates source address information andsource port information of the second target packet into addressinformation and port information of the second device may be that thesource address information and source port information of the secondtarget packet are translated into public IP address information andpublic network port information of the second device respectively.

The following uses a DSL link and an LTE link as an example for detaileddescription. Certainly, in the embodiment of the present invention, thelinks connected to the first device and the second device include butare not limited to the DSL link and LTE link. The link bonding policy isexecuted in step 203. For example, if a DSL link is selected as a targetlink, the second target packet is encapsulated in step 204. A part ofthe encapsulation may be adding address information and port informationof a DSL interface of the first device to obtain the fourth targetpacket, and in step 205, the fourth target packet is sent to the seconddevice through the DSL link.

Optionally, address information and port information in the first targetpacket, second target packet, third target packet, and fourth targetpacket may be shown in the following table:

TABLE 1 Desti- Desti- Source Source nation nation address port addressport First target IP1 1022 IPE 8088 packet Second target IP A/B 2345 IPE8088 packet Fourth target IPA 2345 IPE 8088 packet (DSL) Fourth targetIPB 2345 IPE 8088 packet (LTE) Third target IPD01 4344 IPE 8088 packet

Table 1 may clearly describe a relationship between address informationand port information in the foregoing several packets.

NAT of the first device and second device may be shown in the followingTable 2 and Table 3 respectively. Certainly, this is only an example inthe embodiment of the present invention.

TABLE 2 IP Port obtained obtained Desti- Desti- through through SourceSource nation nation NAT NAT IP port IP port translation translation192.168.2.5 1022 IP E 8088 IP A/B 2345 192.168.2..10 2344 IP E 8088 IPA/B 2346

TABLE 3 IP Port obtained obtained Desti- Desti- through through SourceSource nation nation NAT NAT IP port IP port translation translation IPA/B 2345 IP E 8088 IP D01 4344 IP C/D 5678 IP E 8088 IP D01 4345

In an optional implementation manner, the step of executing a linkbonding policy in step 203 may include analyzing, by the first device, abandwidth parameter of each link that is connected to the first deviceand the second device and spanned by the transparent transmissionchannel; and analyzing, by the first device according to the bandwidthparameter of each link, a speed and a packet length for sending to abuffer of the link, and selecting the target link from the multiplelinks connected to the first device and the second device.

Step 205 may include sending, by the first device, the fourth targetpacket to the buffer of the target link according to the speed andpacket length for sending to the buffer of the target link, and sendingthe fourth target packet in the buffer to the second device through thetarget link.

Optionally, the bandwidth parameter includes at least one of thefollowing a packet transmission rate, a packet transmission delay, apacket transmission jitter, and a buffer queue length.

Optionally, the analyzing, by the first device according to thebandwidth parameter of each link, a speed and a packet length forsending to a buffer of the link may be that the speed and packet lengthfor sending to the buffer of the link may be proportional to a bandwidthparameter of the link, that is, if the bandwidth parameter is better(for example, the packet transmission rate is higher, the packettransmission delay is shorter, the packet transmission jitter issmaller, and the buffer queue length is shorter), the speed of thebuffer of the link is higher and the packet length is longer. In step205, the second target packet is sent to the buffer of the target linkaccording to the speed and packet length for sending to the buffer ofthe target link.

In an optional implementation manner, the analyzing, by the firstdevice, a bandwidth parameter of each link, may include receiving, bythe first device, a bandwidth parameter, which is sent by a thirddevice, of a second network link between the first device and the seconddevice, where the third device is a device of a second network, and thefirst device is a device of a first network.

The second device analyzes a bandwidth parameter of a first network linkbetween the first device and the second device.

Optionally, in this implementation manner, multiple devices may jointlyanalyze bandwidth parameters of links between the first device and thesecond device. Optionally, the first network and second network may beone or more networks. For example, the first device is a DSL gateway,and the third device is an LTE mobile phone, that is, the first networkis a DSL network, and the second network is an LTE network. In this way,the first device may send a packet to the second device through thefirst network and second network separately.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, the number ofencapsulation layers is small, implementation is based on standard, anda packet transmission rate may be improved.

FIG. 3 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 3,the method includes the following.

301. A first device receives, through a transparent transmission channelestablished in advance, a second response packet sent by a seconddevice, where the transparent transmission channel spans multiple linksconnected to the first device and the second device, and the secondresponse packet is a response packet obtained by the second device byperforming NAT on a first response packet, where the first responsepacket is a response packet that is received by the second device from atarget device and sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device.

302. The first device performs NAT on the second response packet toobtain a third response packet.

303. The first device sends the third response packet to a deviceidentified by source address information of the target packet.

Optionally, the transparent transmission channel may refer to thetransparent transmission channel described in the foregoing embodiment.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the first device and the second device are two differentdevices. For example, when the first device is an access device, thesecond device may be a server; when the first device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

Optionally, that the second device performs NAT on a first responsepacket may be that destination address information and destination portinformation of the first response packet are translated into addressinformation and port information of the first device.

Optionally, that the first device performs NAT on the second responsepacket may be that destination address information and destination portinformation of the second response packet are translated into sourceaddress information and source port information of the target packet.

In the foregoing technical solution, a first device receives, through atransparent transmission channel established in advance, a secondresponse packet sent by a second device, where the transparenttransmission channel spans multiple links connected to the first deviceand the second device, and the second response packet is a responsepacket obtained by the second device by performing NAT on a firstresponse packet, where the first response packet is a response packetthat is received by the second device from a target device and sent bythe target device in response to a target packet that is sent in advanceby a first device to the target device; the first device performs NAT onthe second response packet to obtain a third response packet; and thefirst device sends the third response packet to a device identified bysource address information of the target packet. In this way, NAT isperformed when a packet is transmitted between the first device and thesecond device. Therefore, network address resources are saved, a fastforwarding capability of a router on a transmission path may be used,and thereby packet transmission efficiency may be improved.

FIG. 4 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 4,the method includes the following.

401. A second device establishes a transparent transmission channel witha first device, where the transparent transmission channel spansmultiple links connected to the second device and the first device.

402. The second device receives, through the transparent transmissionchannel, a second target packet sent by the first device, where thesecond target packet is a packet obtained by the first device byperforming NAT on a first target packet.

403. The second device performs NAT on the second target packet toobtain a third target packet.

404. The second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the first device and the second device are two differentdevices. For example, when the first device is an access device, thesecond device may be a server; when the first device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

Optionally, that the first device performs NAT on a first target packetmay be that source address information and source port information ofthe first target packet are translated into address information and portinformation of the first device.

Optionally, that the second device performs NAT on the second targetpacket may be that source address information and source portinformation of the second target packet are translated into addressinformation and port information of the second device.

In the foregoing technical solution, a second device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thesecond device and the first device; the second device receives, throughthe transparent transmission channel, a second target packet sent by thefirst device, where the second target packet is a packet obtained by thefirst device by performing NAT on a first target packet; the seconddevice performs NAT on the second target packet to obtain a third targetpacket; and the second device sends the third target packet to a targetdevice identified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the first device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 5 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 5,the method includes the following.

501. A second device performs NAT on a first response packet to obtain asecond response packet, where the first response packet is a responsepacket that is received by the second device from a target device andsent by the target device in response to a target packet that is sent inadvance by a first device to the target device.

502. The second device transmits the second response packet to the firstdevice through a transparent transmission channel established inadvance, so that the first device performs NAT on the second responsepacket to obtain a third response packet, and the first device sends thethird response packet to a device identified by source addressinformation of the target packet, where the transparent transmissionchannel spans multiple links connected to the first device and thesecond device.

Optionally, the transparent transmission channel may refer to thetransparent transmission channel described in the foregoing embodiment.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the first device and the second device are two differentdevices. For example, when the first device is an access device, thesecond device may be a server; when the first device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a second device performs NAT on afirst response packet to obtain a second response packet, where thefirst response packet is a response packet that is received by thesecond device from a target device and sent by the target device inresponse to a target packet that is sent in advance by a first device tothe target device; and the second device transmits the second responsepacket to the first device through a transparent transmission channelestablished in advance, so that the first device performs NAT on thesecond response packet to obtain a third response packet, and the firstdevice sends the third response packet to a device identified by sourceaddress information of the target packet, where the transparenttransmission channel spans multiple links connected to the first deviceand the second device. In this way, NAT is performed when a packet istransmitted between the first device and the second device. Therefore,network address resources are saved, a fast forwarding capability of arouter on a transmission path may be used, and thereby packettransmission efficiency may be improved.

FIG. 6 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 6,the method includes the following.

601. A second device performs NAT on a first response packet to obtain asecond response packet, where the first response packet is a responsepacket that is received by the second device from a target device andsent by the target device in response to a target packet that is sent inadvance by a first device to the target device.

602. The second device executes a link bonding policy, and selects atarget link from links that are connected to the second device and thefirst device and spanned by a transparent transmission channelestablished in advance, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

603. The second device encapsulates the second response packet with thetarget link to obtain a fourth response packet.

604. The second device sends, through the target link, the fourthresponse packet to an interface, on which the target link isestablished, of the first device, obtainso that the first devicedecapsulates the fourth response packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by source address information of the target packet.

Optionally, that a second device performs NAT on a first response packetmay be that destination address information and destination portinformation of the first response packet are translated into addressinformation and port information of the first device.

Optionally, that the first device performs NAT on the second responsepacket may be that destination address information and destination portinformation of the second response packet are translated into sourceaddress information and source port information of the target packet.

In an implementation manner, step 602 may include receiving, by thesecond device, a bandwidth parameter, which is sent by the first device,of each link that is connected to the second device and the first deviceand spanned by the transparent transmission channel established inadvance, where the bandwidth parameter of each link is a bandwidthparameter of each link obtained by the first device by analysis; andanalyzing, by the second device according to the bandwidth parameter ofeach link, a speed and a packet length for sending to a buffer of thelink, and selecting the target link from the multiple links that areconnected to the second device and the first device and spanned by thetransparent transmission channel established in advance.

Step 604 may include sending, by the second device, the fourth responsepacket to the buffer of the target link according to the speed andpacket length for sending to the buffer of the target link, and sendingthe fourth response packet in the buffer to the interface, on which thetarget link is established, of the second device.

Optionally, address information and port information in the firstresponse packet, second response packet, third response packet, andfourthresponse target packet may be shown in the following table:

TABLE 4 Desti- Desti- Source Source nation nation address port addressport First response IPE 8088 IPD01 4344 packet Second response IPE 8088IPA/B 2345 packet Fourth response IPE 8088 IPA 2345 packet (DSL) Fourthresponse IPE 8088 IPB 2345 packet (LTE) Third response IPE 8088 IP1 1022packet

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, standard-based NATtranslation and encapsulation are performed, and a packet forwardingrate may be improved.

FIG. 7 is a schematic flowchart of a multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 7,the method includes the following.

701. A first device establishes a transparent transmission channel witha second device, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

702. The first device translates source address information and sourceport information of a first target packet into address information andport information of the first device to obtain a second target packet.

703. The first device transmits the second target packet to the seconddevice through the transparent transmission channel, so that the seconddevice translates source address information and source port informationof the second target packet into address information and portinformation of the second device to obtain a third target packet, thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket, the second device receives a first response packet sent by thetarget device, and the second device translates destination addressinformation and destination port information of the first responsepacket into the address information and port information of the firstdevice to obtain a second response packet, where the first responsepacket is a response packet sent by the target device according to thethird target packet.

704. The first device receives, through the transparent transmissionchannel, the second response packet sent by the second device, andtranslates destination address information and destination portinformation of the second response packet into the source addressinformation and source port information of the first target packet toobtain a third response packet.

705. The first device sends the third response packet to a deviceidentified by the source address information of the first target packet.

In the foregoing technical solution, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device translates sourceaddress information and source port information of a first target packetinto address information and port information of the first device toobtain a second target packet; the first device transmits the secondtarget packet to the second device through the transparent transmissionchannel, so that the second device translates source address informationand source port information of the second target packet into addressinformation and port information of the second device to obtain a thirdtarget packet, the second device sends the third target packet to atarget device identified by destination address information of the firsttarget packet, the second device receives a first response packet sentby the target device, and the second device translates destinationaddress information and destination port information of the firstresponse packet into the address information and port information of thefirst device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet; the first device receives, through thetransparent transmission channel, the second response packet sent by thesecond device, and translates destination address information anddestination port information of the second response packet into thesource address information and source port information of the firsttarget packet to obtain a third response packet; and the first devicesends the third response packet to a device identified by the sourceaddress information of the first target packet. In this way, NAT isperformed when a packet is transmitted between the first device and thesecond device. Therefore, network address resources are saved, a fastforwarding capability of a router on a transmission path may be used,and thereby packet transmission efficiency may be improved.

FIG. 8 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 8,the method includes the following.

801. A first device establishes a transparent transmission channel witha second device, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

802. The first device translates source address information and sourceport information of a first target packet into address information andport information of the first device to obtain a second target packet.

Optionally, the first target packet may be an uplink packet. Optionally,the first target packet may be one or more packets sent by a user-sidedevice (for example, a home terminal or a mobile terminal), and thefirst device is an access device or a gateway device.

Optionally, the first target packet may be a downlink packet.Optionally, the first target packet may be one or more packets sent byan Internet device, and the first device is an aggregation server.

803. The first device executes a link bonding policy (for example, aLink Channel Policy), and selects a target link from the links that areconnected to the first device and the second device and spanned by thetransparent transmission channel.

804. The first device encapsulates the second target packet with theselected target link to obtain a fourth target packet.

805. The first device transmits the fourth target packet to the seconddevice through the target link, obtain so that the second devicedecapsulates the fourth target packet to obtain a third target packet,the second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket, the second device receives a first response packet sent by thetarget device, and the second device translates destination addressinformation and destination port information of the first responsepacket into the address information and port information of the firstdevice to obtain a second response packet, where the first responsepacket is sent by the target device according to the third targetpacket.

806. The first device receives, through the target link, the secondresponse packet sent by the second device, and translates destinationaddress information and destination port information of the secondresponse packet into the source address information and source portinformation of the first target packet to obtain a third responsepacket.

807. The first device sends the third response packet to a deviceidentified by the source address information of the first target packet.

Optionally, that the second device translates source address informationand source port information of the second target packet into addressinformation and port information of the second device may be that thesource address information and source port information of the secondtarget packet are respectively translated into public IP addressinformation and public network port information of the second device.

The following uses a DSL link and an LTE link as an example for detaileddescription. Certainly, in the embodiment of the present invention, thelinks connected to the first device and the second device include butare not limited to the DSL link and LTE link. The link bonding policy isexecuted in step 803. For example, if a DSL link is selected as a targetlink, the second target packet is encapsulated in step 804. A part ofthe encapsulation may be adding address information and port informationof a DSL interface of the first device to obtain the fourth targetpacket, and in step 805, the fourth target packet is sent to the seconddevice through the DSL link.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, the number ofencapsulation layers is small, implementation is based on standard, anda packet transmission rate may be improved.

FIG. 9 is a schematic flowchart of another multi-link aggregation methodaccording to an embodiment of the present invention. As shown in FIG. 9,the method includes the following.

901. A second device establishes a transparent transmission channel witha first device, where the transparent transmission channel spansmultiple links connected to the second device and the first device.

902. The second device receives, through the transparent transmissionchannel, a second target packet sent by the first device, where thesecond target packet is a packet obtained by the first device bytranslating source address information and source port information of afirst target packet into address information and port information of thefirst device.

903. The second device translates source address information and sourceport information of the second target packet into address informationand port information of the second device to obtain a third targetpacket.

904. The second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

905. The second device receives a first response packet sent by thetarget device, and translates destination address information anddestination port information of the first response packet into theaddress information and port information of the first device to obtain asecond response packet, where the first response packet is a responsepacket sent by the target device according to the third target packet.

906. The second device sends the second response packet to the firstdevice through the transparent transmission channel, so that the firstdevice translates destination address information and destination portinformation of the second response packet into the source addressinformation and source port information of the first target packet toobtain a third response packet, and the first device sends the thirdresponse packet to a device identified by the source address informationof the first target packet.

In the foregoing technical solution, a second device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thesecond device and the first device; the second device receives, throughthe transparent transmission channel, a second target packet sent by thefirst device, where the second target packet is a packet obtained by thefirst device by translating source address information and source portinformation of a first target packet into address information and portinformation of the first device; the second device translates sourceaddress information and source port information of the second targetpacket into address information and port information of the seconddevice to obtain a third target packet; the second device sends thethird target packet to a target device identified by destination addressinformation of the first target packet; the second device receives afirst response packet sent by the target device, and translatesdestination address information and destination port information of thefirst response packet into the address information and port informationof the first device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet; and the second device sends the secondresponse packet to the first device through the transparent transmissionchannel, so that the first device translates destination addressinformation and destination port information of the second responsepacket into the source address information and source port informationof the first target packet to obtain a third response packet, and thefirst device sends the third response packet to a device identified bythe source address information of the first target packet. In this way,NAT is performed when a packet is transmitted between the first deviceand the second device, and thereby packet transmission efficiency may beimproved.

FIG. 10 is a schematic flowchart of another multi-link aggregationmethod according to an embodiment of the present invention. As shown inFIG. 10, the method includes the following.

1001. A second device establishes a transparent transmission channelwith a first device, where the transparent transmission channel spansmultiple links connected to the second device and the first device.

1002. The second device receives, through the transparent transmissionchannel, a second target packet sent by the first device, where thesecond target packet is a packet obtained by the first device bytranslating source address information and source port information of afirst target packet into address information and port information of thefirst device.

Optionally, the first target packet may be an uplink packet. Optionally,the first target packet may be one or more packets sent by a user-sidedevice (for example, a home terminal or a mobile terminal), the firstdevice is an access device or a gateway device, and the second device isan aggregation server.

Optionally, the first target packet may be a downlink packet.Optionally, the first target packet may be one or more packets sent byan Internet device, the first device is an aggregation server, and thesecond device is an access device or a gateway device.

1003. The second device translates source address information and sourceport information of the second target packet into address informationand port information of the second device to obtain a third targetpacket.

1004. The second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

1005. The second device receives a first response packet sent by thetarget device, and translates destination address information anddestination port information of the first response packet into theaddress information and port information of the first device to obtain asecond response packet, where the first response packet is a responsepacket sent by the target device according to the third target packet.

1006. The second device executes a link bonding policy, and selects atarget link from the links that are connected to the second device andthe first device and spanned by the transparent transmission channel.

1007. The second device encapsulates the second response packet with thetarget link to obtain a fourth response packet.

1008. The second device sends, through the target link, the fourthresponse packet to an interface, on which the target link isestablished, of the first device, obtainso that the first devicedecapsulates the fourth response packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by the source address information of the first target packet.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, standard-based NATtranslation and encapsulation are performed, and a packet forwardingrate may be improved.

FIG. 11 is a schematic flowchart of another multi-link aggregationmethod according to an embodiment of the present invention. As shown inFIG. 11, the method includes the following.

1101. A first device establishes a transparent transmission channel witha second device, where the transparent transmission channel spansmultiple links connected to the first device and the second device.

1102. The first device translates source address information and sourceport information of a first target packet into address information andport information of the first device to obtain a second target packet.

1103. The first device transmits the second target packet to the seconddevice through the transparent transmission channel.

1104. The second device translates source address information and sourceport information of the second target packet into address informationand port information of the second device to obtain a third targetpacket.

1105. The second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

1106. The second device receives a first response packet sent by thetarget device, where the first response packet is a response packet sentby the target device according to the third target packet.

1107. The second device translates destination address information anddestination port information of the first response packet into theaddress information and port information of the first device to obtain asecond response packet.

1108. The second device sends the second response packet to the firstdevice through the transparent transmission channel.

1109. The first device translates destination address information anddestination port information of the second response packet into thesource address information and source port information of the firsttarget packet to obtain a third response packet.

1110. The first device sends the third response packet to a sourcedevice identified by the source address information of the first targetpacket.

In the foregoing technical solution, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device translates sourceaddress information and source port information of a first target packetinto address information and port information of the first device toobtain a second target packet; the first device transmits the secondtarget packet to the second device through the transparent transmissionchannel; the second device translates source address information andsource port information of the second target packet into addressinformation and port information of the second device to obtain a thirdtarget packet; the second device sends the third target packet to atarget device identified by destination address information of the firsttarget packet; the second device receives a first response packet sentby the target device, and the second device translates destinationaddress information and destination port information of the firstresponse packet into the address information and port information of thefirst device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet; the first device receives, through thetransparent transmission channel, the second response packet sent by thesecond device, and translates destination address information anddestination port information of the second response packet into thesource address information and source port information of the firsttarget packet to obtain a third response packet; and the first devicesends the third response packet to a source device identified by thesource address information of the first target packet. In this way, NATis performed when a packet is transmitted between the first device andthe second device. Therefore, network address resources are saved, afast forwarding capability of a router on a transmission path may beused, and thereby packet transmission efficiency may be improved.

The following describes apparatus embodiments of the present invention.The apparatus embodiments of the present invention are used to executethe methods in the aboved embodiments of the present invention. For easeof description, only parts related to the embodiments of the presentinvention are described. For specific technical details that are notdisclosed, reference may be made to the above embodiments of the presentinvention.

FIG. 12 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 12, thenetwork device includes an establishing unit 11, a translating unit 12,and a sending unit 13.

The establishing unit 11 is configured to establish a transparenttransmission channel with a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device.

The translating unit 12 is configured to perform NAT on a first targetpacket to obtain a second target packet.

The sending unit 13 is configured to transmit the second target packetto the second device through the transparent transmission channel, sothat the second device performs NAT on the second target packet toobtain a third target packet, and that the second device sends the thirdtarget packet to a target device identified by destination addressinformation of the first target packet.

Optionally, when receiving the second target packet, the second devicemay perform NAT on the packet, and send a packet obtained throughtranslation to the target device.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the network device and the second device are two differentdevices. For example, when the network device is an access device, thesecond device may be a server; when the network device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the network device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the network device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a global system for mobilecommunications (GSM) link, a cable link, a fiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a genericrouting encapsulation (GRE) tunnel, a point-to-point transmissionchannel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; the network device performs NAT ona first target packet to obtain a second target packet; the networkdevice transmits the second target packet to the second device throughthe transparent transmission channel, so that the second device performsNAT on the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the network device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 13 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 13, thenetwork device includes an establishing unit 21, a translating unit 22,a selecting unit 23, an encapsulating unit 24, and a sending unit 25.

The establishing unit 21 is configured to establish a transparenttransmission channel with a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device.

The translating unit 22 is configured to perform NAT on a first targetpacket to obtain a second target packet.

The selecting unit 23 is configured to execute a link bonding policy,and select a target link from the links that are connected to thenetwork device and the second device and spanned by the transparenttransmission channel.

The encapsulating unit 24 is configured to encapsulate the second targetpacket with the target link to obtain a fourth target packet.

The sending unit 25 is configured to transmit the fourth target packetto the second device through the target link, obtain so that the seconddevice decapsulates the fourth target packet to obtain a third targetpacket, and the second device sends the third target packet to a targetdevice identified by destination address information of the first targetpacket.

Optionally, that the first translating unit 22 performs NAT on a firsttarget packet may be that the network device translates source addressinformation and source port information of the first target packet intoaddress information and port information of the network device.

Optionally, that the second device restores and obtains a third targetpacket may be that the fourth target packet is decapsulated to obtainthe second target packet; and that the second device translates sourceaddress information and source port information of the second targetpacket into address information and port information of the seconddevice, the second device translates source address information andsource port information of the second target packet into addressinformation and port information of the second device may be that thesource address information and source port information of the secondtarget packet are translated into public IP address information andpublic network port information of the second device respectively.

In an optional implementation manner, the selecting unit 23 may include:a first analyzing unit (not shown in the figure), configured to analyzea bandwidth parameter of each link that is connected to the networkdevice and the second device and spanned by the transparent transmissionchannel; and a second analyzing unit (not shown in the figure),configured to analyze, according to the bandwidth parameter of eachlink, a speed and a packet length for sending to a buffer of the link,and select the target link from the multiple links connected to thenetwork device and the second device.

The sending unit 25 may be further configured to send the fourth targetpacket to the buffer of the target link according to the speed andpacket length for sending to the buffer of the target link, and send thefourth target packet in the buffer to the second device through thetarget link.

Optionally, the bandwidth parameter includes at least one of thefollowing: a packet transmission rate, a packet transmission delay, apacket transmission jitter, and a buffer queue length.

In an optional implementation manner, the first analyzing unit (notshown in the figure) may be further configured to receive a bandwidthparameter, which is sent by a third device, of a second network linkbetween the network device and the second device, where the third deviceis a device of a second network, and the network device is a device of afirst network, and analyze a bandwidth parameter of a first network linkbetween the network device and the second device.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, the number ofencapsulation layers is small, implementation is based on standard, anda packet transmission rate may be improved.

FIG. 14 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 14, thenetwork device includes a receiving unit 31, a translating unit 32, anda sending unit 33.

The receiving unit 31 is configured to receive, through a transparenttransmission channel established in advance, a second response packetsent by a second device, where the transparent transmission channelspans multiple links connected to the network device and the seconddevice, and the second response packet is a response packet obtained bythe second device by performing NAT on a first response packet, wherethe first response packet is a response packet that is received by thesecond device from a target device and sent by the target device inresponse to a target packet that is sent in advance by the networkdevice to the target device.

The translating unit 32 is configured to perform NAT on the secondresponse packet to obtain a third response packet.

The sending unit 33 is configured to send the third response packet to adevice identified by source address information of the target packet.

Optionally, the transparent transmission channel may refer to thetransparent transmission channel described in the foregoing embodiment.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the network device and the second device are two differentdevices. For example, when the network device is an access device, thesecond device may be a server; when the network device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the network device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the network device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

Optionally, that the second device performs NAT on a first responsepacket may be that destination address information and destination portinformation of the first response packet are translated into addressinformation and port information of the network device.

Optionally, that the network device performs NAT on the second responsepacket may be that destination address information and destination portinformation of the second response packet are translated into sourceaddress information and source port information of the target packet.

In the foregoing technical solution, a network device receives, througha transparent transmission channel established in advance, a secondresponse packet sent by a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device, and the second response packet is aresponse packet obtained by the second device by performing NAT on afirst response packet, where the first response packet is a responsepacket that is received by the second device from a target device andsent by the target device in response to a target packet that is sent inadvance by the network device to the target device; the network deviceperforms NAT on the second response packet to obtain a third responsepacket; and the network device sends the third response packet to adevice identified by source address information of the target packet. Inthis way, NAT is performed when a packet is transmitted between thenetwork device and the second device. Therefore, network addressresources are saved, a fast forwarding capability of a router on atransmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 15 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 15, thenetwork device includes an establishing unit 41, a receiving unit 42, atranslating unit 43, and a sending unit 44.

The establishing unit 41 is configured to establish a transparenttransmission channel with a first device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the first device.

The receiving unit 42 is configured to receive, through the transparenttransmission channel, a second target packet sent by the first device,where the second target packet is a packet obtained by the first deviceby performing NAT on a first target packet.

The translating unit 43 is configured to perform NAT on the secondtarget packet to obtain a third target packet.

The sending unit 44 is configured to send the third target packet to atarget device identified by destination address information of the firsttarget packet.

Optionally, that the first device performs NAT on a first target packetmay be that source address information and source port information ofthe first target packet are translated into address information and portinformation of the first device.

Optionally, that the network device performs NAT on the second targetpacket may be that source address information and source portinformation of the second response packet are translated into addressinformation and port information of the network device.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the first device; the network device receives,through the transparent transmission channel, a second target packetsent by the first device, where the second target packet is a packetobtained by the first device by performing NAT on a first target packet;the network device performs NAT on the second target packet to obtain athird target packet; and the network device sends the third targetpacket to a target device identified by destination address informationof the first target packet. In this way, NAT is performed when a packetis transmitted between the first device and the network device.Therefore, network address resources are saved, a fast forwardingcapability of a router on a transmission path may be used, and therebypacket transmission efficiency may be improved.

FIG. 16 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 16, thenetwork device includes a translating unit 51 and a sending unit 52.

The translating unit 51 is configured to perform NAT on a first responsepacket to obtain a second response packet, where the first responsepacket is a response packet that is received by the network device froma target device and sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device.

The sending unit 52 is configured to transmit the second response packetto the first device through a transparent transmission channelestablished in advance, so that the first device performs NAT on thesecond response packet to obtain a third response packet, and the firstdevice sends the third response packet to a device identified by sourceaddress information of the target packet, where the transparenttransmission channel spans multiple links connected to the first deviceand the network device.

Optionally, the transparent transmission channel may refer to thetransparent transmission channel described in the foregoing embodiment.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device (forexample, a DSL gateway), a server, and a user equipment (for example, amobile phone).

However, the first device and the network device are two differentdevices. For example, when the first device is an access device, thenetwork device may be a server; when the first device is a server, thenetwork device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the networkdevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the network deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a network device performs NAT on afirst response packet to obtain a second response packet, where thefirst response packet is a response packet that is received by thenetwork device from a target device and sent by the target device inresponse to a target packet that is sent in advance by a first device tothe target device; and the network device transmits the second responsepacket to the first device through a transparent transmission channelestablished in advance, so that the first device performs NAT on thesecond response packet to obtain a third response packet, and the firstdevice sends the third response packet to a device identified by sourceaddress information of the target packet, where the transparenttransmission channel spans multiple links connected to the first deviceand the network device. In this way, NAT is performed when a packet istransmitted between the first device and the network device. Therefore,network address resources are saved, a fast forwarding capability of arouter on a transmission path may be used, and thereby packettransmission efficiency may be improved.

FIG. 17 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 17, thenetwork device includes a translating unit 61, a selecting unit 62, anencapsulating unit 63, and a sending unit 63.

The translating unit 61 is configured to perform NAT on a first responsepacket to obtain a second response packet, where the first responsepacket is a response packet that is received by the network device froma target device and sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device.

The selecting unit 62 is configured to execute a link bonding policy,and select a target link from links that are connected to the networkdevice and the first device and spanned by a transparent transmissionchannel established in advance.

The encapsulating unit 63 is configured to encapsulate the secondresponse packet with the target link to obtain a fourth response packet.

The sending unit 64 is configured to send, through the target link, thefourth response packet to an interface, on which the target link isestablished, of the first device, obtain so that the first devicedecapsulates the fourth response packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by source address information of the target packet.

Optionally, that the translating unit 61 performs NAT on a firstresponse packet may be that destination address information anddestination port information of the first response packet are translatedinto address information and port information of the first device.

Optionally, that the first device performs NAT on the second responsepacket may be that destination address information and destination portinformation of the second response packet are translated into sourceaddress information and source port information of the target packet.

In an implementation manner, the selecting unit 62 may include: areceiving subunit (not shown in the figure), configured to receive abandwidth parameter, which is sent by the first device, of each linkthat is connected to the network device and the first device and spannedby the transparent transmission channel established in advance, wherethe bandwidth parameter of each link is a bandwidth parameter of eachlink obtained by the first device by analysis; and an analyzing unit(not shown in the figure), configured to analyze, according to thebandwidth parameter of each link, a speed and a packet length forsending to a buffer of the link, and select the target link from themultiple links that are connected to the network device and the firstdevice and spanned by the transparent transmission channel establishedin advance.

The sending unit 64 may be further configured to send the fourthresponse packet to the buffer of the target link according to the speedand packet length for sending to the buffer of the target link, and sendthe fourth response packet in the buffer to the interface of the firstdevice on which the target link is established.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, standard-based NATtranslation and encapsulation are performed, and a packet forwardingrate may be improved.

FIG. 18 is a schematic structural diagram of a network device accordingto an embodiment of the present invention. As shown in FIG. 18, thenetwork device includes an establishing unit 71, a first translatingunit 72, a first sending unit 73, a receiving unit 74, and a secondsending unit 75.

The establishing unit 71 is configured to establish a transparenttransmission channel with a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device.

The first translating unit 72 is configured to translate source addressinformation and source port information of a first target packet intoaddress information and port information of the network device to obtaina second target packet.

The first sending unit 73 is configured to transmit the second targetpacket to the second device through the transparent transmissionchannel, so that the second device translates source address informationand source port information of the second target packet into addressinformation and port information of the second device to obtain a thirdtarget packet, the second device sends the third target packet to atarget device identified by destination address information of the firsttarget packet, the second device receives a first response packet sentby the target device, and the second device translates destinationaddress information and destination port information of the firstresponse packet into the address information and port information of thenetwork device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet.

The receiving unit 74 is configured to receive, through the transparenttransmission channel, the second response packet sent by the seconddevice, and translate destination address information and destinationport information of the second response packet into the source addressinformation and source port information of the first target packet toobtain a third response packet.

The second sending unit 75 is configured to send the third responsepacket to a device identified by the source address information of thefirst target packet.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user equipment.

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user-side device.

However, the network device and the second device are two differentdevices. For example, when the network device is an access device, thesecond device may be a server; when the network device is a server, thesecond device may be an access device, a gateway device, or a userequipment; when the network device is a user-side device, the seconddevice may be an access device, a gateway device, or a server.

Optionally, the links between the network device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, a point-to-point transmission channel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; the network device translatessource address information and source port information of a first targetpacket into address information and port information of the networkdevice to obtain a second target packet; the network device transmitsthe second target packet to the second device through the transparenttransmission channel, so that the second device translates sourceaddress information and source port information of the second targetpacket into address information and port information of the seconddevice to obtain a third target packet, the second device sends thethird target packet to a target device identified by destination addressinformation of the first target packet, the second device receives afirst response packet sent by the target device, and the second devicetranslates destination address information and destination portinformation of the first response packet into the address informationand port information of the network device to obtain a second responsepacket, where the first response packet is a response packet sent by thetarget device according to the third target packet; the network devicereceives, through the transparent transmission channel, the secondresponse packet sent by the second device, and translates destinationaddress information and destination port information of the secondresponse packet into the source address information and source portinformation of the first target packet to obtain a third responsepacket; and the network device sends the third response packet to adevice identified by the source address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the network device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 19 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.19, the network device includes an establishing unit 81, a firsttranslating unit 82, a selecting unit 83, a second translating unit 84,a first sending unit 85, a receiving unit 86, and a second sending unit87.

The establishing unit 81 is configured to establish a transparenttransmission channel with a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device.

The first translating unit 82 is configured to translate source addressinformation and source port information of a first target packet intoaddress information and port information of the network device to obtaina second target packet.

Optionally, the first target packet may be an uplink packet. Optionally,the first target packet may be one or more packets sent by a user-sidedevice (for example, a home terminal or a mobile terminal), and thenetwork device is an access device or a gateway device.

Optionally, the first target packet may be a downlink packet.Optionally, the first target packet may be one or more packets sent byan Internet device, and the network device is an aggregation server.

The selecting unit 83 is configured to execute a link bonding policy,and select a target link from the links that are connected to thenetwork device and the second device and spanned by the transparenttransmission channel.

The second translating unit 84 is configured to encapsulate the secondtarget packet with the selected target link to obtain a fourth targetpacket.

The first sending unit 85 is configured to transmit the fourth targetpacket to the second device through the target link, obtain so that thesecond device decapsulates the fourth target packet to obtain a thirdtarget packet, the second device sends the third target packet to atarget device identified by destination address information of the firsttarget packet, the second device receives a first response packet sentby the target device, and the second device translates destinationaddress information and destination port information of the firstresponse packet into the address information and port information of thenetwork device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet.

The receiving unit 86 is configured to receive, through the target link,the second response packet sent by the second device, and translatedestination address information and destination port information of thesecond response packet into the source address information and sourceport information of the first target packet to obtain a third responsepacket.

The second sending unit 87 is configured to send the third responsepacket to a device identified by the source address information of thefirst target packet.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described; the number of encapsulation layers is small, and apacket transmission rate may be improved.

FIG. 20 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.20, the network device includes an establishing unit 91, a firstreceiving unit 92, a first translating unit 93, a first sending unit 94,a second receiving unit 95, and a second sending unit 96.

The establishing unit 91 is configured to establish a transparenttransmission channel with a first device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the first device.

The first receiving unit 92 is configured to receive, through thetransparent transmission channel, a second target packet sent by thefirst device, where the second target packet is a packet obtained by thefirst device by translating source address information and source portinformation of a first target packet into address information and portinformation of the first device.

The first translating unit 93 is configured to translate source addressinformation and source port information of the second target packet intoaddress information and port information of the network device to obtaina third target packet.

The first sending unit 94 is configured to send the third target packetto a target device identified by destination address information of thefirst target packet.

The second receiving unit 95 is configured to receive a first responsepacket sent by the target device, and translate destination addressinformation and destination port information of the first responsepacket into the address information and port information of the firstdevice to obtain a second response packet, where the first responsepacket is a response packet sent by the target device according to thethird target packet.

The second sending unit 96 is configured to send the second responsepacket to the first device through the transparent transmission channel,so that the first device translates destination address information anddestination port information of the second response packet into thesource address information and source port information of the firsttarget packet to obtain a third response packet, and the first devicesends the third response packet to a device identified by the sourceaddress information of the first target packet.

Optionally, the address information and port information may betranslated by NAT.

Optionally, when receiving the second target packet, the network devicemay perform NAT on the packet, and send a packet obtained throughtranslation to the target device.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user equipment.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user-side device.

However, the first device and the network device are two differentdevices. For example, when the first device is an access device, thenetwork device may be a server; when the first device is a server, thenetwork device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the networkdevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the network deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, and so on.

Optionally, the first target packet may be one or more packets.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the first device; the network device receives,through the transparent transmission channel, a second target packetsent by the first device, where the second target packet is a packetobtained by the first device by translating source address informationand source port information of a first target packet into addressinformation and port information of the first device; the network devicetranslates source address information and source port information of thesecond target packet into address information and port information ofthe network device to obtain a third target packet; the network devicesends the third target packet to a target device identified bydestination address information of the first target packet; the networkdevice receives a first response packet sent by the target device, andtranslates destination address information and destination portinformation of the first response packet into the address informationand port information of the first device to obtain a second responsepacket, where the first response packet is a response packet sent by thetarget device according to the third target packet; and the networkdevice sends the second response packet to the first device through thetransparent transmission channel, so that the first device translatesdestination address information and destination port information of thesecond response packet into the source address information and sourceport information of the first target packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by the source address information of the first target packet.In this way, NAT is performed when a packet is transmitted between thefirst device and the network device, and thereby packet transmissionefficiency may be improved.

FIG. 21 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.21, the network device includes an establishing unit 101, a firstreceiving unit 102, a first translating unit 103, a first sending unit104, a second receiving unit 105, a selecting unit 106, a secondtranslating unit 107, and a second sending unit 108.

The establishing unit 101 is configured to establish a transparenttransmission channel with a first device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the first device.

The first receiving unit 102 is configured to receive, through thetransparent transmission channel, a second target packet sent by thefirst device, where the second target packet is a packet obtained by thefirst device by translating source address information and source portinformation of a first target packet into address information and portinformation of the first device.

The first translating unit 103 is configured to translate source addressinformation and source port information of the second target packet intoaddress information and port information of the network device to obtaina third target packet.

The first sending unit 104 is configured to send the third target packetto a target device identified by destination address information of thefirst target packet.

The second receiving unit 105 is configured to receive a first responsepacket sent by the target device, and translate destination addressinformation and destination port information of the first responsepacket into the address information and port information of the firstdevice to obtain a second response packet, where the first responsepacket is a response packet sent by the target device according to thethird target packet.

The selecting unit 106 is configured to execute a link bonding policy,and select a target link from the links that are connected to thenetwork device and the first device and spanned by the transparenttransmission channel.

The second translating unit 107 is configured to encapsulate the secondresponse packet with the transparent transmission channel to obtain afourth response packet.

The second sending unit 108 is configured to send, through the targetlink, the fourth response packet to an interface, on which the targetlink is established, of the first device, obtain so that the firstdevice decapsulates the fourth response packet to obtain a thirdresponse packet, and the first device sends the third response packet toa device identified by the source address information of the firsttarget packet.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described; the number of encapsulation layers is small, and apacket transmission rate may be improved.

FIG. 22 is a schematic structural diagram of a multi-link aggregationsystem according to an embodiment of the present invention. As shown inFIG. 22, the system includes a first device 111 and a second device 112.

The first device 111 may be the network device in any one implementationmanner of the embodiments shown in FIG. 12, FIG. 13, FIG. 14, FIG. 18,and FIG. 19.

The second device 112 may be the network device in any oneimplementation manner of the embodiments shown in FIG. 15, FIG. 16, FIG.17, FIG. 20, and FIG. 21.

In the foregoing technical solution, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device performs NAT on afirst target packet to obtain a second target packet; and the firstdevice transmits the second target packet to the second device throughthe transparent transmission channel, so that the second device performsNAT on the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the first device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 23 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.23, the network device includes a memory 121, a transmitter 122, and aprocessor 123 that is connected to the memory 121 and transmitter 122.The memory 121 is configured to store a group of program code. Theprocessor 123 is configured to invoke a program stored in the memory 121to execute the following operations: establishing a transparenttransmission channel with a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device; performing NAT on a first target packet toobtain a second target packet; and controlling the transmitter 122 totransmit the second target packet to the second device through thetransparent transmission channel, so that the second device performs NATon the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket.

In another optional embodiment, the processor 123 may be furtherconfigured to execute the following operations: establishing atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; performing NAT on a first targetpacket to obtain a second target packet; executing a link bonding policy(for example, a Link Channel Policy), and selecting a target link fromthe links that are connected to the network device and the second deviceand spanned by the transparent transmission channel; encapsulating thesecond target packet with the selected target link to obtain a fourthtarget packet; and controlling the transmitter 122 to transmit thefourth target packet to the second device through the target link,obtain so that the second device decapsulates the fourth target packetto obtain a third target packet, and the second device sends the thirdtarget packet to a target device identified by destination addressinformation of the first target packet.

In an optional implementation manner, the operation of executing a linkbonding policy (for example, a Link Channel Policy), and selecting atarget link from the links that are connected to the network device andthe second device and spanned by the transparent transmission channel,which is executed by the processor 123, may include: analyzing abandwidth parameter of each link that is connected to the network deviceand the second device and spanned by the transparent transmissionchannel; and analyzing, according to the bandwidth parameter of eachlink, a speed and a packet length for sending to a buffer of the link,and selecting the target link from the multiple links connected to thenetwork device and the second device.

Optionally, the bandwidth parameter includes at least one of thefollowing: a packet transmission rate, a packet transmission delay, apacket transmission jitter, and a buffer queue length.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; the network device performs NAT ona first target packet to obtain a second target packet; the networkdevice transmits the second target packet to the second device throughthe transparent transmission channel, so that the second device performsNAT on the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the network device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 24 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.24, the network device includes a memory 131, a transmitter 132, areceiver 133, and a processor 134 that is connected to the memory 131,transmitter 132, and receiver 133. The memory 131 is configured to storea group of program code. The processor 134 is configured to invoke aprogram stored in the memory 131 to execute the following operations:controlling the receiver 133 to receive, through a transparenttransmission channel established in advance, a second response packetsent by a second device, where the transparent transmission channelspans multiple links connected to the network device and the seconddevice, and the second response packet is a response packet obtained bythe second device by performing NAT on a first response packet, wherethe first response packet is a response packet that is received by thesecond device from a target device and sent by the target device inresponse to a target packet that is sent in advance by the networkdevice to the target device; performing NAT on the second responsepacket to obtain a third response packet; and controlling thetransmitter 132 to send the third response packet to a device identifiedby source address information of the target packet.

In the foregoing technical solution, a network device receives, througha transparent transmission channel established in advance, a secondresponse packet sent by a second device, where the transparenttransmission channel spans multiple links connected to the networkdevice and the second device, and the second response packet is aresponse packet obtained by the second device by performing NAT on afirst response packet, where the first response packet is a responsepacket that is received by the second device from a target device andsent by the target device in response to a target packet that is sent inadvance by the network device to the target device; the network deviceperforms NAT on the second response packet to obtain a third responsepacket; and the network device sends the third response packet to adevice identified by source address information of the target packet. Inthis way, NAT is performed when a packet is transmitted between thenetwork device and the second device. Therefore, network addressresources are saved, a fast forwarding capability of a router on atransmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 25 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.25, the network device includes a memory 141, a transmitter 142, areceiver 143, and a processor 144 that is connected to the memory 141,transmitter 142, and receiver 143. The memory 141 is configured to storea group of program code. The processor 144 is configured to invoke aprogram stored in the memory 141 to execute the following operations:establishing a transparent transmission channel with a first device,where the transparent transmission channel spans multiple linksconnected to the network device and the first device; controlling thereceiver 143 to receive, through the transparent transmission channel, asecond target packet sent by the first device, where the second targetpacket is a packet obtained by the first device by performing NAT on afirst target packet; performing NAT on the second target packet toobtain a third target packet; and controlling the transmitter 142 tosend the third target packet to a target device identified bydestination address information of the first target packet.

In the foregoing technical solution, a second device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thesecond device and the first device; the second device receives, throughthe transparent transmission channel, a second target packet sent by thefirst device, where the second target packet is a packet obtained by thefirst device by performing NAT on a first target packet; the seconddevice performs NAT on the second target packet to obtain a third targetpacket; and the second device sends the third target packet to a targetdevice identified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the first device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 26 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.26, the network device includes a memory 151, a transmitter 152, and aprocessor 153 that is connected to the memory 151 and transmitter 152.The memory 151 is configured to store a group of program code. Theprocessor 153 is configured to invoke a program stored in the memory 151to execute the following operations: performing NAT on a first responsepacket to obtain a second response packet, where the first responsepacket is a response packet received by the network device from a targetdevice, which is sent by the target device in response to a targetpacket that is sent in advance by a first device to the target device;and controlling the transmitter 152 to transmit the second responsepacket to the first device through a transparent transmission channelestablished in advance, so that the first device performs NAT on thesecond response packet to obtain a third response packet, and the firstdevice sends the third response packet to a device identified by sourceaddress information of the target packet, where the transparenttransmission channel spans multiple links connected to the first deviceand the second device.

In another optional embodiment, the processor 153 may be furtherconfigured to execute the following operations: performing NAT on afirst response packet to obtain a second response packet, where thefirst response packet is a response packet that is received by thesecond device from a target device and sent by the target device inresponse to a target packet that is sent in advance by a first device tothe target device; executing a link bonding policy, and selecting atarget link from links that are connected to the second device and thefirst device and spanned by a transparent transmission channelestablished in advance, where the transparent transmission channel spansmultiple links connected to the first device and the second device;encapsulating the second response packet with the target link to obtaina fourth response packet; and controlling the transmitter 152 to send,through the target link, the fourth response packet to an interface, onwhich the target link is established, of the first device, obtainso thatthe first device decapsulates the fourth response packet to obtain athird response packet, and the first device sends the third responsepacket to a device identified by source address information of thetarget packet.

In another optional implementation manner, the operation of executing alink bonding policy, and selecting a target link from links that areconnected to the second device and the first device and spanned by atransparent transmission channel established in advance, which isexecuted by the processor 153, may include: receiving a bandwidthparameter, which is sent by the first device, of each link that isconnected to the second device and the first device and spanned by thetransparent transmission channel established in advance, where thebandwidth parameter of each link is a bandwidth parameter of each linkobtained by the first device by analysis; and analyzing, according tothe bandwidth parameter of each link, a speed and a packet length forsending to a buffer of the link, and selecting the target link from themultiple links that are connected to the second device and the firstdevice and spanned by the transparent transmission channel establishedin advance.

In the foregoing technical solution, on a basis of the foregoingembodiment, multiple implementation manners of packet transmission aremainly described. In all the implementation manners, standard-based NATtranslation and encapsulation are performed, and a packet forwardingrate may be improved.

FIG. 27 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.27, the network device includes a memory 161, a transmitter 162, areceiver 163, and a processor 164 that is connected to the memory 161,transmitter 162, and receiver 163. The memory 161 is configured to storea group of program code. The processor 164 is configured to invoke aprogram stored in the memory 161 to execute the following operations:establishing a transparent transmission channel with a second device,where the transparent transmission channel spans multiple linksconnected to the network device and the second device; translatingsource address information and source port information of a first targetpacket into address information and port information of the networkdevice to obtain a second target packet; controlling the transmitter 162to transmit the second target packet to the second device through thetransparent transmission channel, so that the second device translatessource address information and source port information of the secondtarget packet into address information and port information of thesecond device to obtain a third target packet, the second device sendsthe third target packet to a target device identified by destinationaddress information of the first target packet, the second devicereceives a first response packet sent by the target device, and thesecond device translates destination address information and destinationport information of the first response packet into the addressinformation and port information of the network device to obtain asecond response packet, where the first response packet is a responsepacket sent by the target device according to the third target packet;controlling the receiver 163 to receive, through the transparenttransmission channel, the second response packet sent by the seconddevice, and translate destination address information and destinationport information of the second response packet into the source addressinformation and source port information of the first target packet toobtain a third response packet; and controlling the transmitter 162 tosend the third response packet to a device identified by the sourceaddress information of the first target packet.

Optionally, the address information and port information may betranslated by NAT (Network Address Translation, NAT).

Optionally, when receiving the second target packet, the second devicemay perform NAT on the packet, and send a packet obtained throughtranslation to the target device.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user equipment.

Optionally, the second device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user-side device.

Optionally, the links between the network device and the second deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a global system for mobilecommunications (GSM) link, a cable link, a fiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a genericrouting encapsulation (GRE) tunnel, a point-to-point transmissionchannel, and so on.

Optionally, the first target packet may be one or more packets.

In another optional embodiment, the processor 164 may be furtherconfigured to execute the following operations: establishing atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; translating source addressinformation and source port information of a first target packet intoaddress information and port information of the network device to obtaina second target packet; executing a link bonding policy (for example, aLink Channel Policy), and selecting a target link from the links thatare connected to the network device and the second device and spanned bythe transparent transmission channel.

The processor 164 may be further configured to execute the followingoperations: encapsulating the second target packet with the selectedtarget link to obtain a fourth target packet; controlling thetransmitter 162 to transmit the fourth target packet to the seconddevice through the target link, obtain so that the second devicedecapsulates the fourth target packet to obtain a third target packet,the second device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket, the second device receives a first response packet sent by thetarget device, and the second device translates destination addressinformation and destination port information of the first responsepacket into the address information and port information of the networkdevice to obtain a second response packet, where the first responsepacket is a response packet sent by the target device according to thethird target packet.

The processor 164 may be further configured to execute the followingoperations: controlling the receiver 163 to receive, through the targetlink, the second response packet sent by the second device, andtranslate destination address information and destination portinformation of the second response packet into the source addressinformation and source port information of the first target packet toobtain a third response packet; and controlling the transmitter 162 tosend the third response packet to a device identified by the sourceaddress information of the first target packet.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the second device; the network device translatessource address information and source port information of a first targetpacket into address information and port information of the networkdevice to obtain a second target packet; the network device transmitsthe second target packet to the second device through the transparenttransmission channel, so that the second device translates sourceaddress information and source port information of the second targetpacket into address information and port information of the seconddevice to obtain a third target packet, the second device sends thethird target packet to a target device identified by destination addressinformation of the first target packet, the second device receives afirst response packet sent by the target device, and the second devicetranslates destination address information and destination portinformation of the first response packet into the address informationand port information of the network device to obtain a second responsepacket, where the first response packet is a response packet sent by thetarget device according to the third target packet; the network devicereceives, through the transparent transmission channel, the secondresponse packet sent by the second device, and translates destinationaddress information and destination port information of the secondresponse packet into the source address information and source portinformation of the first target packet to obtain a third responsepacket; and the network device sends the third response packet to adevice identified by the source address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the network device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

FIG. 28 is a schematic structural diagram of another network deviceaccording to an embodiment of the present invention. As shown in FIG.28, the network device includes a memory 171, a transmitter 172, areceiver 173, and a processor 174 that is connected to the memory 171,transmitter 172, and receiver 173. The memory 171 is configured to storea group of program code. The processor 174 is configured to invoke aprogram stored in the memory 171 to execute the following operations:establishing a transparent transmission channel with a first device,where the transparent transmission channel spans multiple linksconnected to the network device and the first device; controlling thereceiver 173 to receive, through the transparent transmission channel, asecond target packet sent by the first device, where the second targetpacket is a packet obtained by the first device by translating sourceaddress information and source port information of a first target packetinto address information and port information of the first device.

The processor 174 may be further configured to execute the followingoperations: translating source address information and source portinformation of the second target packet into address information andport information of the network device to obtain a third target packet;controlling the transmitter 172 to send the third target packet to atarget device identified by destination address information of the firsttarget packet. The processor 174 may be further configured to executethe following operations: controlling the receiver 173 to receive afirst response packet sent by the target device, and translatedestination address information and destination port information of thefirst response packet into the address information and port informationof the first device to obtain a second response packet, where the firstresponse packet is a response packet sent by the target device accordingto the third target packet; and controlling the transmitter 172 to sendthe second response packet to the first device through the transparenttransmission channel, so that the first device translates destinationaddress information and destination port information of the secondresponse packet into the source address information and source portinformation of the first target packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by the source address information of the first target packet.

Optionally, the address information and port information may betranslated by NAT.

Optionally, when receiving the second target packet, the network devicemay perform NAT on the packet, and send a packet obtained throughtranslation to the target device.

Optionally, the first device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user equipment.

Optionally, the network device may include but is not limited to any oneof the following devices: an access device, a gateway device, a server,and a user-side device.

However, the first device and the network device are two differentdevices. For example, when the first device is an access device, thenetwork device may be a server; when the first device is a server, thenetwork device may be an access device, a gateway device, or a userequipment; when the first device is a user-side device, the networkdevice may be an access device, a gateway device, or a server.

Optionally, the links between the first device and the network deviceinclude but are not limited to any one of the following links: a DSLlink, an LTE link, an FTTX link, an E1 link, a GSM link, a cable link, afiber optic link, and so on.

Optionally, the transparent transmission channel includes but is notlimited to any one of the following channels: a VPN tunnel, a GREtunnel, and so on.

Optionally, the first target packet may be one or more packets.

In another optional embodiment, the processor 174 may be furtherconfigured to execute the following operations: establishing atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the first device; controlling the receiver 173 toreceive, through the transparent transmission channel, a second targetpacket sent by the first device, where the second target packet is apacket obtained by the first device by translating source addressinformation and source port information of a first target packet intoaddress information and port information of the first device;translating source address information and source port information ofthe second target packet into address information and port informationof the network device to obtain a third target packet; controlling thetransmitter 172 to send the third target packet to a target deviceidentified by destination address information of the first targetpacket; controlling the receiver 173 to receive a first response packetsent by the target device, and translate destination address informationand destination port information of the first response packet into theaddress information and port information of the first device to obtain asecond response packet, where the first response packet is a responsepacket sent by the target device according to the third target packet;executing a link bonding policy, and selecting a target link from thelinks that are connected to the network device and the first device andspanned by the transparent transmission channel; encapsulating thesecond response packet with the target link to obtain a fourth responsepacket; and controlling the transmitter 172 to send, through the targetlink, the fourth response packet to an interface, on which the targetlink is established, of the first device, obtain so that the firstdevice decapsulates the fourth response packet to obtain a thirdresponse packet, and the first device sends the third response packet toa device identified by the source address information of the firsttarget packet.

In the foregoing technical solution, a network device establishes atransparent transmission channel with a first device, where thetransparent transmission channel spans multiple links connected to thenetwork device and the first device; the network device receives,through the transparent transmission channel, a second target packetsent by the first device, where the second target packet is a packetobtained by the first device by translating source address informationand source port information of a first target packet into addressinformation and port information of the first device; the network devicetranslates source address information and source port information of thesecond target packet into address information and port information ofthe network device to obtain a third target packet; the network devicesends the third target packet to a target device identified bydestination address information of the first target packet; the networkdevice receives a first response packet sent by the target device, andtranslates destination address information and destination portinformation of the first response packet into the address informationand port information of the first device to obtain a second responsepacket, where the first response packet is a response packet sent by thetarget device according to the third target packet; and the networkdevice sends the second response packet to the first device through thetransparent transmission channel, so that the first device translatesdestination address information and destination port information of thesecond response packet into the source address information and sourceport information of the first target packet to obtain a third responsepacket, and the first device sends the third response packet to a deviceidentified by the source address information of the first target packet.In this way, NAT is performed when a packet is transmitted between thefirst device and the network device, and thereby packet transmissionefficiency may be improved.

FIG. 29 is a schematic structural diagram of a multi-link aggregationsystem according to an embodiment of the present invention. As shown inFIG. 29, the system includes a first device 181 and a second device 182.

The first device 181 may be the network device in any one implementationmanner of the embodiments shown in FIG. 23, FIG. 24, and FIG. 27.

The second device 182 may be the network device in any oneimplementation manner of the embodiments shown in FIG. 25, FIG. 26, andFIG. 28.

In the foregoing technical solution, a first device establishes atransparent transmission channel with a second device, where thetransparent transmission channel spans multiple links connected to thefirst device and the second device; the first device performs NAT on afirst target packet to obtain a second target packet; and the firstdevice transmits the second target packet to the second device throughthe transparent transmission channel, so that the second device performsNAT on the second target packet to obtain a third target packet, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket. In this way, NAT is performed when a packet is transmittedbetween the first device and the second device. Therefore, networkaddress resources are saved, a fast forwarding capability of a router ona transmission path may be used, and thereby packet transmissionefficiency may be improved.

A person of ordinary skill in the art may understand that all or a partof the processes of the methods in the embodiments may be implemented bya computer program instructing relevant hardware. The program may bestored in a computer readable storage medium. When the program runs, theprocesses of the methods in the embodiments are performed. The foregoingstorage medium may include a magnetic disk, an optical disc, a read-onlymemory (ROM), or a random access memory (RAM).

The disclosed are merely exemplary embodiments of the present invention,but are not intended to limit the scope of the present invention.Equivalent variation figured out according to the claims shall fallwithin the protection scope of the present invention.

What is claimed is:
 1. A multi-link aggregation method comprising:establishing, by a first device, a transparent transmission channel witha second device, the transparent transmission channel comprising aplurality of links between the first device and the second device,wherein the plurality of links support different access technologies,and each of the plurality of links connecting the first device to thesecond device; performing, by the first device when a first targetpacket comprising first source address information and first source portinformation is to be transmitted to a second device, network addresstranslation on the first target packet to obtain a second target packetcomprising second source address information and second source portinformation, the first source address information identifying a sourcedevice of the first target packet, and performing the network addresstranslation comprising translating the first source address informationand the first source port information of the first target packet intoaddress information and port information of the first device, whereinthe second source address information comprises the address informationof the first device, and the second source port information comprisesthe port information of the first device; selecting a target link fromthe plurality of links for transmission of the first target packetthrough the transparent transmission channel; and transmitting, by thefirst device, the second target packet to the second device through theselected target link in the transparent transmission channel, whereinthe second device performs network address translation on the secondtarget packet to obtain a third target packet by translating the secondsource address information and the second source port information of thesecond target packet into address information and port information ofthe second device, and the second device sends the third target packetto a target device identified by destination address information of thefirst target packet, wherein the first target packet, the second targetpacket, and the third target packet comprise the same payload.
 2. Themethod according to claim 1, wherein, after performing the networkaddress translation and before transmitting the second target packet tothe second device, the method further comprises: executing, by the firstdevice, a link bonding policy for selecting the target link from theplurality of links; and encapsulating, by the first device, the secondtarget packet with the target link to obtain a fourth target packet; andwherein transmitting, by the first device, the second target packet tothe second device comprises: transmitting, by the first device, thefourth target packet to the second device through the target link. 3.The method according to claim 2, wherein: the executing comprises:analyzing, by the first device, a bandwidth parameter of each of theplurality of links; and analyzing, by the first device according to thebandwidth parameter of each of the plurality of links, a speed and apacket length for sending to a buffer of a respective link, andselecting the target link from the plurality of links; and whereintransmitting, by the first device, the fourth target packet to thesecond device through the target link, comprises: sending, by the firstdevice, the fourth target packet to the buffer of the target linkaccording to the speed and packet length for sending to the buffer ofthe target link, and sending the fourth target packet in the buffer tothe second device through the target link.
 4. A multi-link aggregationmethod comprising: performing, by a second device when a first responsepacket comprising first destination address information and firstdestination port information is to be transmitted to a first device,network address translation on the first response packet to obtain asecond response packet comprising second destination address informationand second destination port information, the first destination addressinformation identifying the second device, wherein the first responsepacket is a response packet that is received by the second device from atarget device and sent by the target device in response to a targetpacket that is sent in advance by the first device to the target device,performing the network address translation comprising translating thefirst destination address information and the first destination portinformation of the first response packet into address information andport information of the first device, wherein the second destinationaddress information comprises the address information of the firstdevice and the second destination port information comprises the portinformation of the first device; selecting a target link from aplurality of links in a transparent transmission channel established inadvance between the second device and the first device, each of theplurality of links connecting the second device to the first device andthe plurality of links supporting different access technologies; andtransmitting, by the second device, the second response packet to thefirst device through the target link in the transparent transmissionchannel, so that the first device performs network address translationon the second response packet to obtain a third response packet bytranslating the second destination address information and the seconddestination port information into source address information and sourceport information of the target packet, and the first device sends thethird response packet to a device identified by the source addressinformation of the target packet, wherein the first response packet, thesecond response packet, and the third response packet comprise the samepayload.
 5. The method according to claim 4, wherein, after performing,by the second device, the network address translation on the firstresponse packet and before transmitting, by the second device, thesecond response packet to the first device, the method furthercomprises: executing, by the second device, a link bonding policy forselecting the target link from the plurality of links; encapsulating, bythe second device, the second response packet with the target link toobtain a fourth response packet; and wherein transmitting, by the seconddevice, the second response packet to the first device through thetransparent transmission channel, comprises: sending, by the seconddevice through the target link, the fourth response packet to aninterface, on which the target link is established, of the first device.6. The method according to claim 5, wherein executing, by the seconddevice, the link bonding policy comprises: receiving, by the seconddevice, a bandwidth parameter, which is sent by the first device, ofeach of the plurality of links, wherein a bandwidth parameter of eachlink is obtained by the first device by analysis; analyzing, by thesecond device according to the bandwidth parameter of each link, a speedand a packet length for sending to a buffer of the respective link, andselecting the target link from the plurality of links; and wherein thesending, by the second device through the target link, the fourthresponse packet to an interface, on which the target link isestablished, of the first device, comprises: sending, by the seconddevice, the fourth response packet to the buffer of the target linkaccording to the speed and packet length for sending to the buffer ofthe target link, and sending the fourth response packet in the buffer tothe interface, on which the target link is established, of the firstdevice.
 7. A network device, comprising: a processor; and a memorystoring a program to be executed by the processor, the programcomprising instructions to: establish a transparent transmission channelwith a second device, wherein the transparent transmission channel spansa plurality of links between the network device and the second device,the plurality of links supporting different access technologies andconnect the network device with the second device, perform, when a firsttarget packet comprising first source address information and firstsource port information is to be transmitted to a second device, networkaddress translation on the first target packet to obtain a second targetpacket comprising second source address information and second sourceport information, the first source address information identifying asource device of the first target packet, and the network addresstranslation comprising translating the first source address informationand the first source port information of the first target packet intoaddress information and port information of the network device, whereinthe second source address information comprises the address informationof the network device, and the second source port information comprisesthe port information of the network device; select a target link fromthe plurality of links for transmission of the first target packetthrough the transparent transmission channel; and transmit the secondtarget packet to the second device through the target link in thetransparent transmission channel, so that the second device performsnetwork address translation on the second target packet to obtain athird target packet by translating the second source address informationand the second source port information of the second target packet intoaddress information and port information of the second device, and thesecond device sends the third target packet to a target deviceidentified by destination address information of the first targetpacket, wherein the first target packet, the second target packet, andthe third target packet comprise the same payload.
 8. The network deviceaccording to claim 7, wherein the program further comprises instructionsto: execute a link bonding policy for selecting the target link from theplurality of links; encapsulate the second target packet with the targetlink to obtain a fourth target packet, wherein address information andport information of an interface of the network device corresponding tothe target link is added to obtain the fourth target packet; andtransmit the fourth target packet to the second device through thetarget link.
 9. The network device according to claim 8, wherein theprogram further comprises instructions to: analyze a bandwidth parameterof each of the plurality of links; analyze, according to the bandwidthparameter of each of the plurality of links, a speed and a packet lengthfor sending to a buffer of the respective link, and select the targetlink from the plurality of links; and send the fourth target packet tothe buffer of the target link according to the speed and packet lengthfor sending to the buffer of the target link, and send the fourth targetpacket in the buffer to the second device through the target link.
 10. Anetwork device, comprising: a processor; and a memory storing a programto be executed by the processor, the program comprising instructions to:perform, when a first response packet comprising first destinationaddress information and first destination port information is to betransmitted to a first device, network address translation on the firstresponse packet to obtain a second response packet comprising seconddestination address information and second destination port information,the first destination address information identifying the networkdevice, wherein the first response packet is a response packet that isreceived by the network device from a target device and sent by thetarget device in response to a target packet that is sent in advance bythe first device to the target device, the network address translationcomprising translating the first destination address information and thefirst destination port information of the first response packet intoaddress information and port information of the first device, whereinthe second destination address information comprises the addressinformation of the first device and the second destination portinformation comprises the port information of the first device; select atarget link from a plurality of links in a transparent transmissionchannel established in advance between the network device and the firstdevice, the plurality of links connecting the network device with thefirst device and supporting different access technologies; and transmitthe second response packet to the first device through the target linkin the transparent transmission channel, so that the first deviceperforms network address translation on the second response packet toobtain a third response packet by translating the second destinationaddress information and the second destination port information intosource address information and source port information of the targetpacket, and the first device sends the third response packet to a deviceidentified by the source address information of the target packet,wherein the first response packet, the second response packet, and thethird response packet comprise the same payload.
 11. The network deviceaccording to claim 10, wherein the program further comprisesinstructions to: execute a link bonding policy for selecting the targetlink from the plurality of links; encapsulate the second response packetwith the target link to obtain a fourth response packet; and send,through the target link, the fourth response packet to an interface, onwhich the target link is established, of the first device.
 12. Thenetwork device according to claim 11, wherein the program furthercomprises instructions to: receive a bandwidth parameter, which is sentby the first device, of each of the plurality of links, wherein abandwidth parameter of each link is obtained by the first device byanalysis; analyze, according to the bandwidth parameter of each link, aspeed and a packet length for sending to a buffer of the respectivelink, and select the target link from the plurality of links; and sendthe fourth response packet to the buffer of the target link according tothe speed and packet length for sending to the buffer of the targetlink, and send the fourth response packet in the buffer to theinterface, on which the target link is established, of the networkdevice.
 13. The method according to claim 1, wherein the transparenttransmission channel comprises more than one access technology.
 14. Themethod according to claim 4, wherein the transparent transmissionchannel comprises more than one access technology.
 15. The networkdevice according to claim 7, wherein the transparent transmissionchannel comprises more than one access technology.
 16. The networkdevice according to claim 10, wherein the transparent transmissionchannel comprises more than one access technology.